Vehicle brake rotor and method of making same

ABSTRACT

A vehicle brake rotor is provided, including manufacturing a friction ring with an opening, an annular flange projecting axially relative to a face of the friction ring, and a plurality of spaced lugs projecting radially from the flange. A hub is manufactured with a plurality of recesses integrally upon the friction ring. Next, the hub is manufactured or machined so that outermost ends of the lugs are visible from an exterior of the hub.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 14/817,833 filed on Aug. 4, 2015, the entirety ofwhich is incorporated herein by reference.

BACKGROUND

The invention generally relates to vehicle brakes, and more specificallyto an improved vehicle brake rotor, and a process for making same.

Vehicle brake rotors are known and typically include a friction ring ordisc to which is fastened a hub used to connect the ring to a vehiclewheel. As is well known, friction rings have opposing friction surfacesfor engagement by brake pads mounted in vehicle calipers such that eachof two pads engage a corresponding surface of the friction ring underdriver control to stop the vehicle. The friction ring of the vehiclebrake rotor rotates about a central axis, coincident with the rotationalaxis of the wheel to which it is attached.

To reduce vehicle brake rotor weight, and improve the vehicle brakerotor's heat dissipation efficiency, brake rotors made of two materialshave become both more popular and common, particularly among high-endvehicles. Friction rings are typically cast from a ferrous material,such as cast or grey iron. The friction rings are then machined inmultiple operations to shape the rotor and form an inner mountingsection and the friction surfaces. The friction surfaces of the rotorare also machined to a predetermined tolerance range.

The hub of a vehicle brake rotor is typically cast from metallicmaterials such as aluminum. A conventional hub further includes acentrally located bore, and a plurality of equally spaced fastenermounting holes formed circumferentially in a mounting surface around thebore. Hubs are connected to the disc body, usually with a plurality offasteners such as rivets, or threaded fasteners, such as screws. Byconnecting the hub to the friction ring, fasteners keep the hub andfriction ring together. As a result, fasteners aid in movement of thevehicle brake rotor.

To accurately assemble the brake rotors made of two materials,complicated equipment is needed. Due to the high level of skill neededto operate such complicated equipment, the costs of manufacturing thetwo material vehicle brake rotor with fasteners are high.

Another drawback of conventional bi-metallic brake rotors is that a hubmade of lighter materials has a higher expansion rate than the frictionring made of cast iron. When the vehicle brake rotor undergoes hightemperature conditions, expansion of the hub and the friction ring willoccur. Such expansion will further occur when the vehicle brake rotorand friction rings engage. There is a concern that multi-component brakerotors will be subject to shorter operational life due to the differentexpansion and contraction properties of the materials used inproduction. Thus, there is a need for an improved technique formanufacturing vehicle brake rotors.

SUMMARY

The above-listed needs and drawbacks are addressed by an improvedvehicle brake rotor designed to be constructed so that the friction ringand the hub are connected to each other without fasteners. Vehicle brakerotors made according to the present process are simpler and lessexpensive to manufacture. Further, vehicle brake rotors withoutfasteners are more reliable, and have a longer lifespan, because thepossibilities of the fasteners touching the friction ring are reduced. Amethod for making the brake rotor without fasteners, and a brake rotormade by such a process are thus disclosed as a solution to the problemsdescribed above.

The process works by first manufacturing a friction ring conventionallymade of gray iron, or other heavy metal. In a preferred embodiment,there are two of the manufactured friction rings, each having an edgeand a face, and being connected by conventional materials used to jointwo friction rings. One of the faces of the friction rings has anannular flange projecting axially relative to the face of the frictionring. On an exterior surface of the annular flange, a preferably equallydistributed plurality of spaced lugs project radially from the annularflange. An interior surface of the annular flange has an interior grooveor flat surface.

The present brake rotor features the hub being integrally joined to thefriction ring. The friction ring is placed into a cavity correspondingof an embed casting mold. Once this is accomplished, a molten materialconventional in embed casting, such as aluminum, is poured into thecavity, and covers the lugs and the flange of the friction ring. As themolten aluminum cools, the hub is formed and is integrally joined to thefriction ring. Once this is accomplished, the positive and negativechambers of the embed casting mold are removed, and the combinedfriction ring and hub are withdrawn from the mold. Next, an exteriorperipheral edge of the hub is manufactured or machined, such thatoutermost ends of lugs on the annular flange are visible.

More specifically, a method of making a vehicle brake rotor is provided,including, manufacturing a friction ring with an opening, an annularflange projecting axially relative to a face of the friction ring, and aplurality of spaced lugs projecting radially from the flange. A hub ismanufactured with a plurality of recesses integrally upon the frictionring. Next, the hub is manufactured or machined so that outermost endsof the lugs are visible from an exterior of the hub.

In another embodiment, a vehicle brake rotor is provided, including afriction ring with an opening, an annular flange projecting axiallyrelative to a face of the friction ring that defines the opening and aplurality of spaced lugs projecting radially from the flange. A hub isprovided with a plurality of recesses matingly engaging the lugs, anendcap covering the opening of the hub, and the hub is integrally joinedto the friction ring. After machining or manufacturing the hub,outermost ends of the lugs of the brake rotor are visible from anexterior of the hub.

In yet another embodiment, a vehicle brake rotor manufactured by aprocess is provided, including the steps of manufacturing a frictionring with an opening, an annular flange projecting axially relative to aface of the friction ring, and a plurality of spaced lugs projectingradially from the flange. Manufacturing a hub with a plurality ofrecesses upon the friction ring, each recess engaging a correspondinglug, and joining the hub integrally to the friction ring. The hub isthen machined or manufactured so that outermost ends of the lugs arevisible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of an assembled friction ring, and ahub forming the present vehicle brake rotor;

FIG. 2 is a vertical cross-section taken along the line 2-2 of FIG. 1and in the direction generally indicated;

FIG. 3 is an exploded front perspective view of the present frictionring and the hub before the friction ring and hub are integrally joined;

FIG. 4 is a front perspective of the present vehicle brake rotor withthe hub integrally formed upon the friction ring, preferably via embedcasting;

FIG. 5 is a vertical cross-section taken along the line 5-5 of FIG. 4and in the direction generally designated;

FIG. 6 is a vertical cross-section of an embed casting mold used to makethe present vehicle brake rotor;

FIG. 7 is a vertical cross-section of another embodiment of the presentvehicle brake rotor; and

FIG. 8 is a vertical cross-section of still another embodiment of thepresent vehicle brake rotor.

DETAILED DESCRIPTION

Referring now to FIGS. 1-3, the present vehicle brake rotor, generallydesignated 10, is configured to be mounted to a vehicle wheel, notshown. As is known in the art, the rotational axis of the vehicle brakerotor 10 is coincident with the rotational axis of the wheel to which itis attached.

The present vehicle brake rotor 10 has a friction ring 12. In thepreferred embodiment, the friction ring 12 is made of gray iron, orother suitable metals, alloys or other materials used in conventionalfriction rings. The friction ring 12 is also made up of a pair ofgenerally parallel plates 12 a and 12 b, each having an edge 14, and aface 16. Joining the friction rings 12 a and 12 b is a plurality ofconnectors 18. On the face 16 of the friction ring 12 a are an axiallyprojecting annular flange 20, and an opening 22 of the friction ringdefined by the annular flange 20. Projecting radially from the axiallyprojecting annular flange 20 is a plurality of lugs 24. The annularflange 20 also includes an interior wall 26. A hub 28 is integrallyjoined to the flange 20, preferably by embed casting. In the preferredembodiment, the hub is composed of aluminum or other metals. On top ofthe hub 28 is an endcap 30.

Casting the hub 28 upon the friction ring 12 produces a plurality ofrecesses 32, which matingly engage the lugs 24 projecting radially fromthe annular flange 20. The hub 28 also engages the annular flange 20 viaan interior groove 34. The lugs 24 are concentric with the recesses 32on hub 28, and are preferably spaced equidistantly. While in thepreferred embodiment the lugs 24 are generally cylindrical in shape,other shapes are contemplated, including various polygonal shapes (whenviewed in transverse cross-section). As seen in FIG. 3, after the hub 28is cast, the lugs 24 are completely covered by the hub.

The rotor 10 is mounted to the vehicle wheel using mounting holes 36 inthe endcap 30, and a central opening 38 engages an axle shaft (notshown). The vehicle brake rotor 10 is mounted to a wheel of, forexample, an automotive vehicle on the inboard side of the wheel, withrespect to the assembled vehicle, for stopping the rotation of the wheelin operation of the vehicle. Conventionally, four such vehicle brakerotors 10 are used on a vehicle, one with each of the four wheels.However, some older vehicles are equipped with only two front diskbrakes, the rear brakes being drum-type.

Referring now to FIGS. 4 and 5, the vehicle brake rotor 10 is shownintegrally joined to the friction ring 12 before the hub 28 ismanufactured or machined. In this application, “manufactured” will beunderstood to refer to any of a variety of fabricating steps commonlyknown to skilled practitioners, including casting, grinding, fastening,or the like. As the hub 28 is joined integrally to the friction ring 12the endcap 30 on the hub partially covers the opening 22. As seen inFIG. 3, the lugs 24 are completely covered by the hub 28.

Referring now to FIG. 6, in the preferred embodiment of the presentvehicle brake rotor 10, the friction ring 12 and the hub 28 areintegrally joined by embed casting, using a mold generally designated40, including two mating portions 40 a, 40 b as is well known in theart. Once the friction ring 12 is cast and suitably machined, it isplaced into a corresponding cavity 42 of the mold 40. A molten material44, typically aluminum, or another suitable alloy, is then poured into achamber 46 of the embed casting mold 40. As the molten material 44 flowsdown the chamber 46, it forms the hub 28, The high temperatures of themolten material 44 cause the friction ring 12 to expand, and interiorgroove 34 of the hub matingly engages the flange 20. Also, the lugs 24matingly engage the recesses 32, located in a skirt 48 of the hub 28.

After the molten material 44 cools, the friction ring 12 and the hub 28are integrally joined to each other, and the lugs 24 are matinglyreceived in the recesses 32. After cooling, the joined hub 28 andfriction ring is then machined so that outermost ends 50 of the lugs 24are visible from an exterior of the rotor 10 (FIGS. 1 and 2). While inthe preferred embodiment, the ends 50 are circular, other shapes arecontemplated, depending on the cross-sectional geometry of the lugs 24as discussed above.

Referring now to FIG. 7, an alternate embodiment of the present vehiclebrake rotor 10 is generally designated 60. Components shared with therotor 10 are designated with identical reference numbers. A majordifference between the rotor 60 and the rotor 10 is that the flange 20is provided with an annular groove 62 which matingly engages acorresponding annular tongue 64 in the hub 28.

Referring now to FIG. 8, another alternate embodiment of the presentvehicle brake rotor 10 is generally designated 70. Components sharedwith the rotors 10 and 60 are designated with identical referencenumbers. A main feature of the rotor 70 is that the annular flange 20 isprovided with an outermost flat surface 72 that engages a correspondingflat surface 74 on the hub 28.

While a particular embodiment of the vehicle brake rotor and method ofmaking same has been described herein, it will be appreciated by thoseskilled in the art that changes, and modifications may be made theretowithout departing from the invention in its broader aspects and as setforth in the following claims.

1. A vehicle brake rotor, comprising: a friction ring with an opening,an annular flange projecting axially relative to a face of the frictionring that defines the opening, and a plurality of spaced lugs projectingradially from the flange; and, a hub with a plurality of recessesmatingly engaging said lugs and an endcap covering said openingintegrally joined to said friction ring, wherein one of said annularflange and said hub includes an annular groove radially spaced from thelugs and surrounded by the other of said annular flange and said hub andthe annular groove matingly engaging an annular tongue in the other ofsaid annular flange and said hub, wherein outermost ends of said lugsare visible from an exterior of said hub, and, wherein the outermostends of said lugs do not extend radially beyond the hub.
 2. The vehiclebrake rotor of claim 1, wherein the friction ring is made of gray iron.3. The vehicle brake rotor of claim 1, wherein the hub is made ofaluminum.
 4. The vehicle brake rotor of claim 1, wherein said hub isintegrally joined to said friction ring by embed casting.
 5. The vehiclebrake rotor of claim 4, wherein said hub is provided with an endcapcovering said opening.
 6. The vehicle brake rotor of claim 5, whereinthe hub is made of aluminum
 7. The vehicle brake rotor of claim 1,wherein the outermost ends of the lugs are visible from an exterior ofsaid hub after manufacturing said hub is made by machining said hub, andsaid ends are circular.
 8. The vehicle brake rotor of claim 1, whereinsaid hub is manufactured on said friction ring so that said outermostends of the lugs are not visible from an exterior of said hub frictionring, and then said hub is manufactured on said friction ring so thatsaid outermost ends of the lugs are visible from an exterior of saidhub.
 9. The vehicle brake rotor of claim 1, wherein the lugs of thefriction ring are concentric with the recesses on the hub and are spacedequidistantly.
 10. A vehicle brake rotor obtained by a processcomprising: manufacturing a friction ring with an opening, an annularflange projecting axially relative to a face of the friction ring, and aplurality of spaced lugs projecting radially from the flange;manufacturing a hub with a plurality of recesses upon said frictionring, joining said hub integrally to said friction ring so thatoutermost ends of said lugs are not visible from an exterior of saidhub; and manufacturing said hub on said friction ring so that outermostends of said lugs are visible from an exterior of said hub to form thevehicle brake rotor, wherein said vehicle brake rotor comprises: one ofsaid annular flange and said hub including an annular groove radiallyspaced from the lugs and surrounded by the other of said annular flangeand said hub and the annular groove matingly engaging an annular tonguein the other of said annular flange and said hub and, wherein theoutermost ends of said lugs do not extend radially beyond the hub. 11.The vehicle brake rotor of claim 10, wherein the friction ring is madeof gray iron.
 12. The vehicle brake rotor of claim 10, wherein the hubis made of aluminum.
 13. The vehicle brake rotor of claim 10, whereinsaid hub is integrally joined to said friction ring by embed casting.14. The vehicle brake rotor of claim 10, wherein said hub is providedwith an endcap covering said opening.
 15. The vehicle brake rotor ofclaim 10, wherein manufacturing said hub until said outermost ends ofsaid lugs are visible from an exterior of said hub occurs by machiningsaid hub.
 16. The vehicle brake rotor of claim 15, wherein the hub ismade of aluminum
 17. The vehicle brake rotor of claim 10, wherein theoutermost ends of the lugs are visible from an exterior of said hubafter manufacturing said hub is made by machining said hub, and saidends are circular.
 18. The vehicle brake rotor of claim 10, wherein thelugs of the friction ring are concentric with the recesses on the hub,and are spaced equidistantly.
 19. The vehicle brake rotor of claim 10,wherein the hub is made of aluminum and wherein said hub is integrallyjoined to said friction ring by embed casting.
 20. The vehicle brakerotor of claim 19, wherein manufacturing said hub until said outermostends of said lugs are visible from an exterior of said hub occurs bymachining said hub.